Chromosomal aneusomies detected by fluorescent in situ hybridization analysis in clinically localized prostate...

Fluorescent in situ hybridization using 12 chromosome enumeration probes (for chromosomes 4, 6, 7, 8, 9, 10, 11, 12, 17, 18, X and Y) was used to evaluate fresh tumor touch preparations from 40 randomly selected radical prostatectomy specimens. Of the tumors 16 (40%) contained chromosomal aneusomies. Chromosome 8 was aneusomic in 9 tumors (23%). Gain of chromosome 7 was observed in 8 tumors (20%). Chromosome 17 was aneusomic in 4 cases, and chromosomes 10, 11, 12, 18 and Y were each aneusomic twice. Loss of chromosome 9 was observed in 1 tumor. Chromosomes 4, 6, and X were never aneusomic. The percentage of monosomy 17 nuclei was 2 to 4 times the amount noted with the other autosomes for tumor and benign tissue. Computer analysis demonstrated that these signals contained twice the signal density and were significantly different (p < 0.0001) than the single diploid chromosome 17 signals. This result is consistent with homologous pairing of chromosome 17 in benign and neoplastic prostate tissue. Anomalies of chromosomes 8 and/or 7 were present in 14 of the 16 cases (88%) aneusomic by fluorescent in situ hybridization. High grade tumors were more likely to be aneuploid on fluorescent in situ hybridization (p < 0.001). Tumors with chromosome 8 aneusomies were of higher stage (p < 0.05). Fluorescent in situ hybridization is more sensitive than flow cytometry for the detection of aneusomy/aneuploidy. The prognostic relevance of these findings will require further investigation.